[Feat/#23] 행사 신청서 폼 조회·신청 API 추가

api/app-api/build.gradle.kts

@@ -7,6 +7,7 @@ description = "학생 앱 — STUDENT, /v1/app/**"
 dependencies {
     implementation(project(":api:common-api"))
     implementation(project(":core:common"))
+    implementation(project(":core:domain:event"))
     implementation(project(":gateway:auth"))
     implementation(project(":gateway:logging"))
 

api/app-api/src/main/java/kr/ac/kookmin/stream/event/AppEventController.java

@@ -0,0 +1,37 @@
+package kr.ac.kookmin.stream.event;
+
+import jakarta.validation.Valid;
+import kr.ac.kookmin.stream.ApiResponse;
+import kr.ac.kookmin.stream.app.AppApiUser;
+import kr.ac.kookmin.stream.event.domain.event.service.EventService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/v1/app/events")
+@RequiredArgsConstructor
+public class AppEventController {
+
+    private final EventService eventService;
+
+    @GetMapping("/{eventId}/form")
+    public ApiResponse<EventFormResponse> getApplicationForm(@PathVariable Long eventId) {
+        return ApiResponse.success(EventFormResponse.from(eventService.getApplicationForm(eventId)));
+    }
+
+    @PostMapping("/{eventId}/applications")
+    public ApiResponse<EventApplyResponse> apply(
+        AppApiUser apiUser,
+        @PathVariable Long eventId,
+        @Valid @RequestBody EventApplyRequest request
+    ) {
+        return ApiResponse.success(
+            EventApplyResponse.from(eventService.apply(eventId, apiUser.userId(), request.toCommand()))
+        );
+    }
+}

api/app-api/src/main/java/kr/ac/kookmin/stream/event/EventApplyRequest.java

@@ -0,0 +1,32 @@
+package kr.ac.kookmin.stream.event;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotNull;
+import java.util.List;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplyCommand;
+
+public record EventApplyRequest(
+    @NotNull(message = "신청서 답변 목록을 입력해 주세요.")
+    @Valid
+    List<@NotNull(message = "답변 항목이 비어 있습니다.") AnswerRequest> answers
+) {
+
+    public EventApplyCommand toCommand() {
+        return new EventApplyCommand(answers.stream().map(AnswerRequest::toCommand).toList());
+    }
+
+    /**
+     * @param selectedOptions 선택형 질문에서 고른 선택지의 0-based 인덱스
+     */
+    public record AnswerRequest(
+        @NotNull(message = "답변 대상 질문을 입력해 주세요.")
+        Long questionId,
+        String answerText,
+        List<Integer> selectedOptions
+    ) {
+
+        public EventApplyCommand.AnswerCommand toCommand() {
+            return new EventApplyCommand.AnswerCommand(questionId, answerText, selectedOptions);
+        }
+    }
+}

api/app-api/src/main/java/kr/ac/kookmin/stream/event/EventApplyResponse.java

@@ -0,0 +1,23 @@
+package kr.ac.kookmin.stream.event;
+
+import java.time.LocalDateTime;
+import kr.ac.kookmin.stream.event.domain.event.domain.Event;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplicationResult;
+
+public record EventApplyResponse(
+    Long applicationId,
+    String title,
+    LocalDateTime eventStartAt,
+    String place
+) {
+
+    public static EventApplyResponse from(EventApplicationResult result) {
+        Event event = result.getEvent();
+        return new EventApplyResponse(
+            result.getApplicationId(),
+            event.getTitle(),
+            event.getEventStartAt(),
+            event.getPlace()
+        );
+    }
+}

api/app-api/src/main/java/kr/ac/kookmin/stream/event/EventFormQuestionResponse.java

@@ -0,0 +1,29 @@
+package kr.ac.kookmin.stream.event;
+
+import java.util.List;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventQuestion;
+import kr.ac.kookmin.stream.event.domain.event.domain.QuestionType;
+
+public record EventFormQuestionResponse(
+    Long questionId,
+    String questionText,
+    QuestionType questionType,
+    boolean isRequired,
+    int displayOrder,
+    List<String> options,
+    Integer maxLength
+) {
+
+    public static EventFormQuestionResponse from(EventQuestion question) {
+        QuestionType questionType = question.getQuestionType();
+        return new EventFormQuestionResponse(
+            question.getId(),
+            question.getQuestionText(),
+            questionType,
+            question.isRequired(),
+            question.getDisplayOrder(),
+            question.getOptions() == null ? List.of() : question.getOptions(),
+            questionType.maxLength()
+        );
+    }
+}

api/app-api/src/main/java/kr/ac/kookmin/stream/event/EventFormResponse.java

@@ -0,0 +1,26 @@
+package kr.ac.kookmin.stream.event;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import kr.ac.kookmin.stream.event.domain.event.domain.Event;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplicationForm;
+
+public record EventFormResponse(
+    Long eventId,
+    String title,
+    LocalDateTime eventStartAt,
+    String place,
+    List<EventFormQuestionResponse> questions
+) {
+
+    public static EventFormResponse from(EventApplicationForm form) {
+        Event event = form.getEvent();
+        return new EventFormResponse(
+            event.getId(),
+            event.getTitle(),
+            event.getEventStartAt(),
+            event.getPlace(),
+            form.getQuestions().stream().map(EventFormQuestionResponse::from).toList()
+        );
+    }
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/Event.java

@@ -48,4 +48,56 @@ public static Event of(
             applyEndAt, recruitType, imageIds, capacity, recruitStatus, createdBy
         );
     }
+
+    /**
+     * 현재 시각과 신청자 수를 반영한 모집 상태를 계산한다.
+     * <p>
+     * 저장된 recruitStatus는 운영진의 강제 마감만을 뜻하므로, 신청 기간과 잔여 정원을 함께 봐야 실제 상태가 나온다.
+     * 행사 상세 조회·신청서 폼 조회·행사 신청이 같은 기준을 써야 하므로 도메인에 둔다.
+     *
+     * @param appliedCount status가 APPLIED인 신청 수. 선착순 모집이 아니면 쓰이지 않는다
+     */
+    public RecruitStatus calculateRecruitStatus(LocalDateTime now, long appliedCount) {
+        if (isForceClosed() || isAfterApplyPeriod(now)) {
+            return RecruitStatus.CLOSED;
+        }
+        if (isBeforeApplyPeriod(now)) {
+            return RecruitStatus.BEFORE_OPEN;
+        }
+        if (isCapacityFull(appliedCount)) {
+            return RecruitStatus.CLOSED;
+        }
+        return RecruitStatus.OPEN;
+    }
+
+    /**
+     * 정원이 찼는지 판정한다. 선착순 모집에만 정원 제한이 있고, 상시 모집은 인원 제한이 없다.
+     */
+    public boolean isCapacityFull(long appliedCount) {
+        return recruitType == RecruitType.FIRST_COME && appliedCount >= capacity;
+    }
+
+    /**
+     * 정원 때문에만 닫힌 상태인지. 모집 상태 계산은 강제 마감·기간 종료·정원 마감을 모두 CLOSED로 합치지만,
+     * 신청 실패 사유는 이 둘을 구분해야 하므로 정원이 유일한 사유일 때를 따로 판정한다.
+     */
+    public boolean isClosedByCapacityOnly(LocalDateTime now, long appliedCount) {
+        return !isForceClosed()
+            && !isBeforeApplyPeriod(now)
+            && !isAfterApplyPeriod(now)
+            && isCapacityFull(appliedCount);
+    }
+
+    /** 운영진이 강제로 마감했는지. 저장된 recruitStatus는 이 뜻만 갖는다. */
+    private boolean isForceClosed() {
+        return recruitStatus == RecruitStatus.CLOSED;
+    }
+
+    private boolean isBeforeApplyPeriod(LocalDateTime now) {
+        return now.isBefore(applyStartAt);
+    }
+
+    private boolean isAfterApplyPeriod(LocalDateTime now) {
+        return now.isAfter(applyEndAt);
+    }
 }

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/EventApplicationForm.java

@@ -0,0 +1,23 @@
+package kr.ac.kookmin.stream.event.domain.event.domain;
+
+import java.util.List;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+
+/**
+ * 신청서 폼 조회 결과. 행사 요약과 질문 목록을 함께 돌려주기 위한 읽기 모델이다.
+ */
+@Getter
+@EqualsAndHashCode
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+public class EventApplicationForm {
+
+    private Event event;
+    private List<EventQuestion> questions;
+
+    public static EventApplicationForm of(Event event, List<EventQuestion> questions) {
+        return new EventApplicationForm(event, questions);
+    }
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/EventApplicationResult.java

@@ -0,0 +1,22 @@
+package kr.ac.kookmin.stream.event.domain.event.domain;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+
+/**
+ * 행사 신청 결과. 생성된 신청 식별자와 행사 요약을 함께 돌려주기 위한 읽기 모델이다.
+ */
+@Getter
+@EqualsAndHashCode
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+public class EventApplicationResult {
+
+    private Long applicationId;
+    private Event event;
+
+    public static EventApplicationResult of(Long applicationId, Event event) {
+        return new EventApplicationResult(applicationId, event);
+    }
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/EventApplyCommand.java

@@ -0,0 +1,26 @@
+package kr.ac.kookmin.stream.event.domain.event.domain;
+
+import java.util.List;
+
+/**
+ * 행사 신청 요청. 질문별 답변 목록을 담는다.
+ */
+public record EventApplyCommand(List<AnswerCommand> answers) {
+
+    /**
+     * 질문 하나에 대한 답변.
+     *
+     * @param answerText      단답형·장문형 답변. 선택형이면 null
+     * @param selectedOptions 선택형 질문에서 고른 선택지의 0-based 인덱스. 주관식이면 빈 목록
+     */
+    public record AnswerCommand(Long questionId, String answerText, List<Integer> selectedOptions) {
+
+        /**
+         * 답변 내용이 비어 있는지. 선택 질문은 생략과 빈 답변을 같게 취급하므로 판정 기준을 한곳에 둔다.
+         */
+        public boolean isEmpty() {
+            return (answerText == null || answerText.isBlank())
+                && (selectedOptions == null || selectedOptions.isEmpty());
+        }
+    }
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/EventErrorCode.java

@@ -0,0 +1,22 @@
+package kr.ac.kookmin.stream.event.domain.event.domain;
+
+import kr.ac.kookmin.stream.common.ErrorCode;
+import kr.ac.kookmin.stream.common.ErrorStatus;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(fluent = true)
+@AllArgsConstructor
+public enum EventErrorCode implements ErrorCode {
+
+    EVENT_NOT_FOUND(ErrorStatus.NOT_FOUND, "행사를 찾을 수 없습니다."),
+    ALREADY_CLOSED(ErrorStatus.CONFLICT, "행사 마감되었습니다."),
+    CAPACITY_FULL(ErrorStatus.CONFLICT, "모집 정원이 마감되었습니다."),
+    ALREADY_APPLIED(ErrorStatus.CONFLICT, "이미 신청한 행사입니다."),
+    INVALID_ANSWER(ErrorStatus.BAD_REQUEST, "신청서 답변 형식이 올바르지 않습니다.");
+
+    private final int status;
+    private final String message;
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/domain/QuestionType.java

@@ -1,8 +1,20 @@
 package kr.ac.kookmin.stream.event.domain.event.domain;
 
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(fluent = true)
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
 public enum QuestionType {
-    SHORT_TEXT,
-    LONG_TEXT,
-    SINGLE_CHOICE,
-    MULTIPLE_CHOICE
+
+    SHORT_TEXT(50),
+    LONG_TEXT(500),
+    SINGLE_CHOICE(null),
+    MULTIPLE_CHOICE(null);
+
+    /** 답변 길이 제한. 선택형 질문은 답변이 텍스트가 아니라 null이다. */
+    private final Integer maxLength;
 }

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/repository/EventRepository.java

@@ -0,0 +1,23 @@
+package kr.ac.kookmin.stream.event.domain.event.repository;
+
+import java.util.List;
+import java.util.Optional;
+import kr.ac.kookmin.stream.event.domain.event.domain.Event;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplication;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplicationAnswer;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventQuestion;
+
+public interface EventRepository {
+
+    Optional<Event> findById(Long id);
+
+    List<EventQuestion> findQuestionsByEventId(Long eventId);
+
+    long countAppliedByEventId(Long eventId);
+
+    boolean existsAppliedByEventIdAndMemberId(Long eventId, Long memberId);
+
+    EventApplication saveApplication(EventApplication application);
+
+    List<EventApplicationAnswer> saveAnswers(List<EventApplicationAnswer> answers);
+}

core/domain/event/src/main/java/kr/ac/kookmin/stream/event/domain/event/service/EventService.java

@@ -0,0 +1,12 @@
+package kr.ac.kookmin.stream.event.domain.event.service;
+
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplicationForm;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplicationResult;
+import kr.ac.kookmin.stream.event.domain.event.domain.EventApplyCommand;
+
+public interface EventService {
+
+    EventApplicationForm getApplicationForm(Long eventId);
+
+    EventApplicationResult apply(Long eventId, Long memberId, EventApplyCommand command);
+}